U.S. patent number 5,357,438 [Application Number 08/070,817] was granted by the patent office on 1994-10-18 for anti-collision system for vehicles.
Invention is credited to Dan Davidian.
United States Patent |
5,357,438 |
Davidian |
October 18, 1994 |
Anti-collision system for vehicles
Abstract
An anti-collision system for vehicles includes a speed sensor
for sensing the speed of the vehicle, a space sensor for measuring
the distance of the vehicle from an object, a computer for
computing a danger-of-collision distance to the object, an alarm
actuated by the computer when the sensed distance of the object is
equal to or less than the danger-of-collision distance compared by
the computer, and a brake light actuated upon the actuation of said
alarm. The system also includes a control panel having parameter
presetting means for presetting preselected parameters concerning
the vehicle, the vehicle driver, and the environment, which are
utilized by the computer for computing the danger-of-collision
distance to the object.
Inventors: |
Davidian; Dan (Holon,
IL) |
Family
ID: |
11063690 |
Appl.
No.: |
08/070,817 |
Filed: |
June 3, 1993 |
Foreign Application Priority Data
Current U.S.
Class: |
701/301; 701/96;
342/455; 180/169; 340/436 |
Current CPC
Class: |
G01S
13/931 (20130101); B60Q 9/008 (20130101); B60K
37/06 (20130101); G01S 2013/9324 (20200101); G01S
2013/93272 (20200101); G01S 2013/9322 (20200101); G01S
2013/93271 (20200101); G01S 7/046 (20130101); G01S
2013/9317 (20130101); G01S 2013/9323 (20200101); G01S
2013/93185 (20200101); G01S 2013/932 (20200101); G01S
2013/9325 (20130101); G01S 13/60 (20130101); G01S
2013/93274 (20200101) |
Current International
Class: |
B60K
37/04 (20060101); B60K 37/06 (20060101); B60Q
1/50 (20060101); B60Q 1/52 (20060101); G01S
13/00 (20060101); G01S 13/93 (20060101); G01S
7/04 (20060101); G01S 13/60 (20060101); G06F
015/50 () |
Field of
Search: |
;364/460,461,424.01,424.04,426.04 ;340/435,436,437,438,961
;342/29,41,455 ;434/236,238,258 ;273/440 ;180/167-169 ;73/517A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chin; Gary
Attorney, Agent or Firm: Barish; Benjamin J.
Claims
What is claimed is:
1. An anti-collision system for moving vehicles, comprising:
means for determining the speed of a moving vehicle;
means for measuring the distance of the moving vehicle from an
object;
a computer for receiving a number of parameters, including the
speed of the vehicle, and for computing from said parameters a
danger-of-collision distance to said object;
and a collision alarm actuated by said computer when the measured
distance of said object is equal to or less than said
danger-of-collision distance computed by the computer;
characterized in that said system also includes a control panel
having parameter presetting means for presetting preselected
parameters which are utilized by said computer for computing said
danger-of-collision distance to said object;
said preselected parameters including at least one vehicle
parameter concerning a preselected condition of the vehicle, and at
least one environmental parameter concerning a preselected
condition of the environment.
2. The system according to claim 1, wherein the system also
includes a safety alarm actuated by said computer, before actuating
said collision alarm, when said measured distance is equal to or
less than said danger-of-collision distance multiplied by a
predetermined safety factor.
3. The system according to claim 2, wherein said control panel also
includes distance presetting means for presetting a selected fixed
distance from said object, said computer being effective to actuate
one of said alarms when the distance to said object is equal to or
less than said fixed distance.
4. The system according to claim 1, wherein said preselected
parameters further include:
at least one driver parameter concerning a preselected condition of
the vehicle driver.
5. The system according to claim 4, wherein said driver parameter
includes a selected one of a plurality of relative reaction times
of the vehicle driver.
6. The system according to claim 1, wherein said vehicle parameter
includes a selected one of a plurality of relative load conditions
of the vehicle.
7. The system according to claim 1, wherein said environmental
parameter includes a selected parameter indicative of the danger of
the road to skidding.
8. The system according to claim 1, wherein said environmental
parameter includes a selected parameter indicative of the
visibility condition at the time of driving.
9. The system according to claim 1, wherein said environmental
parameter includes a selected parameter indicative of the type of
road over which the vehicle is travelling.
10. The system according to claim 1, wherein said environmental
parameter includes a selected parameter indicative of whether or
not it is daylight at the time of driving.
11. The system according to claims 1, wherein said presetting means
includes a plurality of depressible keys on said control panel.
12. The system according to claim 1, wherein said vehicle includes
a brake light indicator which is automatically actuated when said
collision alarm is actuated.
13. The system according to claim 2, wherein said vehicle includes
a brake light indicator which is automatically actuated when said
safety alarm is actuated.
14. The system according to claim 1, wherein said control panel
includes presettable means for disabling said collision alarm when
said measure distance, said determined speed, or the product of
said measured distance and said determined speed is less than a
predetermined minimum.
15. The system according to claim 1, further including a plurality
of condition sensors for sensing any one of a plurality of, said
selected conditions, and for automatically feeding to said computer
information with respect to said sensed conditions, said
information also being utilized by the computer for computing said
danger-of-collision distance to said object.
16. The system according to claim 15, wherein said condition
sensors include a condition-of-driver sensor, comprising:
a plurality of depressible keys including a start key and further
keys;
means effective upon depressing the start key for displaying a
random sequence in which said further keys are to be depressed;
and means for comparing the actual sequence in which said further
keys are depressed with said displayed random sequence to provide a
condition-of-driver parameter, which said condition-of-driver
parameter is also utilized by the computer for enabling or
disabling vehicle operation or for computing said
danger-of-collision distance to said object.
17. The system according to claim 1, wherein said system further
includes a sealed recording device which records all incidents in
which said computer actuated said alarm including the time, speed
and relative distance between the vehicle and said object for each
incident.
18. The system according to claim 1, wherein said system further
includes an actuator for automatically actuating a mechanical
system of the vehicle at the time said collision alarm is
actuated.
19. An anti-collision system for moving vehicles, comprising:
means for determining the speed of a moving vehicle;
means for measuring the distance of the moving vehicle from an
object;
a computer for receiving a number of parameters, including the
speed of the vehicle, and for computing from said parameters a
danger-of-collision distance to said object;
and a collision alarm actuated by said computer when the measured
distance of said object is equal to or less than said
danger-of-collision distance computed by the computer;
characterized in that said system also includes a control panel
having parameter presetting means for presetting preselected
parameters which are utilized by said computer for computing said
danger-of-collision distance to said object;
said preselected parameters including at least one vehicle
parameter concerning the load carried by the vehicle, and at least
one driver parameter concerning a preselected condition of the
vehicle driver.
20. An anti-collision system for moving vehicles, comprising:
means for determining the speed of a moving vehicle;
means for measuring the distance of the moving vehicle from an
object;
a computer for receiving a number of parameters, including the
speed of the vehicle, and for computing from said parameters a
danger-of-collision distance to said object;
and a collision alarm actuated by said computer when the measured
distance of said object is equal to or less than said
danger-of-collision distance computed by the computer;
characterized in that said system also includes a control panel
having parameter presetting means for presetting preselected
parameters which are utilized by said computer for computing said
danger-of-collision distance to said object;
said preselected parameters including at least one driver parameter
concerning a preselected condition of the vehicle driver, and at
least one environmental parameter concerning a preselected
condition of the environment.
Description
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to an anti-collision system for
vehicles. The invention is especially useful for passenger cars,
taxis, trucks and buses, and is therefore described below
particularly with respect to such vehicles, but the invention, or
some aspects of the invention, could also advantageously be used
for other types of vehicles, e.g., trains and aircraft.
One of the most frequent causes of vehicle accidents is the failure
of a vehicle to maintain an assured safe distance behind another
vehicle to prevent a rear end collision should the front vehicle
suddenly stop. The assured safe distance required to prevent such a
rear-end collision depends on the reaction time of the vehicle
driver before the brake pedal is actually depressed, and the
braking distance traversed by the vehicle before it comes to a
complete stop after the braking pedal has been depressed. Both of
these factors vary according to the surrounding circumstances at
the time of driving.
In order to prevent collisions, many parameters, which are
constantly changing during the year or even during a trip, may
affect the stopping distance of the vehicle and therefore should be
taken into account. These parameters include: the condition of the
driver, such as the driver's reaction time; the condition of the
vehicle, such as the vehicle load, the tires pressure; and
environmental conditions, such as road type, visibility, skidding
condition.
It is very important that the computer determines the
danger-of-collision distance according to the specific conditions
existing at the time the vehicle is being operated. Thus, if the
determined danger-of-collision distance is too high for the
specific operating conditions, there will be a high rate of "false
alarms"; this will reduce the credibility of the system to the
driver, which can result in a true collision condition being
ignored. 0n the other hand, if the determined danger-of-collision
distance is too low for the specific operating conditions, this
could result in failure to actuate the alarm in time when there was
truly a collision condition.
Many anti-collision systems have been proposed, but insofar as I am
aware, none has yet gained any widespread use, probably because the
proposed systems have not taken into consideration the variable
nature of the many parameters which influence the reaction time
and/or the braking distance involved at any particular time for
determining the assured safe distance required to be
maintained.
An object of the present invention is to provide an anti-collision
system which is more closely responsive to the actual driving
conditions for actuating an alarm.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, there is provided an
anti-collision system for vehicles, comprising: means for
determining the speed of the vehicle; means for measuring the
distance of the vehicle from an object; a computer for receiving a
number of parameters, including the speed of the vehicle, and for
computing from the parameters a danger-of-collision distance to the
object; and a Collision alarm actuated by the computer when the
measured distance of the object is equal to or less than the
danger-of-collision distance computed by the computer;
characterized in that the system also includes a control panel
having parameter presetting means for presetting preselected
parameters which are utilized by the computer for computing the
danger-of-collision distance to the object.
According to further features in the preferred embodiment of the
invention described below, the system also includes a Safety alarm
actuated by the computer, before actuating the Collision alarm,
when the measured distance is equal to or less than the
danger-of-collision distance multiplied by a predetermined safety
factor.
According to further features in the described preferred
embodiment, below, the control panel also includes distance
presetting means for presetting a selected fixed distance from an
object, the computer being effective to actuate the Collision alarm
also when the sensed distance to the object is equal to or less
than the fixed distance.
According to still further features in the described preferred
embodiment, the preselected parameters include: at least one
vehicle parameter concerning a preselected condition of the
vehicle; at least one driver parameter concerning a preselected
condition of the vehicle driver; and at least one environmental
parameter concerning a preselected condition of the environment. In
the described preferred embodiment, the presetting is effected by a
plurality of depressible keys on the control panel.
The system described below also includes a plurality of condition
sensors for sensing any one of a plurality of selected conditions,
and for automatically feeding to the computer information with
respect to the sensed conditions, which information is also
utilized by the computer for computing the danger-of-collision
distance to the object. One of the described condition sensors
includes a condition-of-driver sensor comprising a plurality of
depressible keys, means for displaying a random sequence in which
the latter keys are to be depressed, and means for comparing the
actual sequence in which the keys are depressed with the displayed
random sequence to provide a condition-of-driver parameter, which
parameter is also utilized by the computer for enabling or
disabling vehicle operation and/or for computing the
danger-of-collision distance to the object.
According to another feature in the described preferred embodiment,
the system further includes a sealed recording device which records
all incidents in which the computer actuates the alarms.
As will be described more particularly below, an anti-collision
system constructed in accordance with some or all of the foregoing
features enables the system to be more closely responsive to the
actual conditions at the time of driving the vehicle, including the
condition of the vehicle, the driver, and the environment, in
determining the danger-of-collision distance to avoid a rear-end
collision. Such a system is useful not only for passenger vehicles,
but also for other types of vehicles, such as trucks and buses. The
condition-of-driver sensor referred to above, and also the sealed
recording device, are particularly useful in buses, trucks, trains
and aircraft, to test the condition of the driver, to assure that
the driver is in proper condition for driving the vehicle, and/or
to maintain a record which can be later checked as to all incidents
in which an alarm was actuated by the computer.
According to a further feature, the system includes an actuator for
actuating a mechanical system of the vehicle, e.g., the brakes of a
train, or steering of an aircraft, at the time the collision alarm
is actuated.
Further features and advantages of the invention will be apparent
from the description below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with
reference to the accompanying drawings, wherein:
FIG. 1 diagrammatically illustrates one form of vehicle equipped
with an anti-collision system in accordance with the present
invention;
FIG. 2 illustrates an example of the system control panel to be
mounted in the driver's compartment to enable presetting various
parameters and also to display various information;
FIG. 3 illustrates another type of control panel that may be used
in the anti-collision system;
FIG. 4 illustrates examples of menu-type displays which may be
included in the control panel of FIG. 3;
FIG. 5 illustrates a driving ability test device used as a
condition-of-driver sensor for sensing the condition of the driver
and/or for enabling or disabling operation of the vehicle;
FIGS. 6A and 6B illustrates the microcomputer in the anti-collision
system of FIG. 1 and all the inputs into and the outputs
therefrom;
FIG. 7 is a circuit diagram illustrating one form of electrical
circuit which may be used;
FIG. 8 illustrates one example of a pattern of pulses that may be
used by the vehicle in determining its distance from an object;
FIG. 9 is a flow chart illustrating the overall operation of the
system;
FIGS. 10A-10B, together, constitute flow charts illustrating the
overall operation of the Calculation module in the microcomputer of
FIGS. 6A and 6B;
FIG. 11A-11H, together, constitute flow charts illustrating the
operation of the deceleration alarm module in the microcomputer of
FIGS. 6A and 6B;
FIGS. 12A-12B, together, constitute flow charts illustrating the
operation of the output data module in the microcomputer of FIGS.
6A and 6B;
FIGS. 13A-13B, together, constitute flow charts illustrating the
operation of the black box module in the microcomputer of FIGS. 6A
and 7B;
FIGS. 14A-14D, together, constitute flow charts illustrating the
operation of the driving ability test module in the microcomputer
of FIGS. 6A and 6B;
FIG. 15 illustrates another control panel which may be used to
include additional presettable parameters; and
FIG. 16 illustrates a control panel particularly useful with
trains.
DESCRIPTION OF PREFERRED EMBODIMENTS
Overall System
The anti-collision system illustrated in FIGS. 1-14 is particularly
useful for motor vehicles (passengers cars, buses, trucks) in order
to actuate an alarm when the vehicle is travelling at a distance
behind another vehicle or in front of another, which is equal to or
less than a danger-of-collision distance computed by a computer
such that if the front vehicle stops suddenly there is a danger of
a rear-end collision. For this purpose, the system includes means
for continuously determining the speed of the vehicle; means for
measuring the distance and computing the relative speed between it
and the other vehicle or object; presettable means for presetting
various conditions of the vehicle, vehicle driver and/or
environment; and sensors for automatically sensing other
conditions. All of these are taken into consideration by the
computer for determining the danger-of-collision distance. By thus
taking into consideration all the foregoing parameters, which may
vary widely under varying driving conditions, the system is more
closely responsive to the actual conditions existing at the time
the vehicle is operated, and therefore provides a more creditable
alarm.
In the system described below, there are two alarms: a Collision
alarm, which is actuated when the vehicle is determined to be
within the danger-of-collision distance; and a Safety alarm, which
is actuated before the Collision alarm, at a distance greater than
the danger-of-collision distance by a predetermined safety factor,
e.g., 1.25. For example, if the danger-of-collision distance is
determined to be 100 feet for particular driving conditions, the
Safety alarm will be actuated when the vehicle is within 125 feet,
and if this distance continues to decrease, the Collision alarm
will be actuated when the vehicle reaches 100 feet from the object.
The Safety alarm alerts the driver and is preferably both an
interrupted beep and a continuous visual indicator on the panel;
whereas the Collision alarm is preferably a continuous,
higher-intensity beep and a flashing visual indicator on the
control panel.
The control panel also includes a distance presetting means for
presetting a selected fixed distance from an object, so that when a
constant distance alarm is made effective the driver can maintain a
fixed distance behind another vehicle if he so desires. The
computer is effective to actuate one of the alarms, e.g., the
Safety alarm, when the distance to the object is equal to or less
than the fixed distance.
Automatic sensors
FIG. 1 diagrammatically illustrates, for purposes of example, a
plurality of automatic sensors and other electrical devices
included in a vehicle equipped with an anti-collision system
constructed in accordance with the present invention.
Thus, the vehicle, generally designated 2, is equipped with a
microcomputer 4 having a control panel 6 installed in the passenger
compartment of the vehicle at a location conveniently accessible to
the driver. FIGS. 2 and 3, to be described below, illustrate two
types of control panels that may be used for this purpose.
Vehicle 2 further includes a front space sensor 8 for sensing the
space in front of the vehicle, such as the presence of another
vehicle, a corresponding rear space sensor 10, and a pair of side
sensors 11. All the space sensors are in the form of pulse (e.g.,
ultrasonic) transmitters and receivers, for determining the
distance of the vehicle from an object, e.g., another vehicle, at
front or rear. Space sensors may also be provided at the sides of
the vehicle. Vehicle 2 is further equipped with a speed sensor 12
which may sense the speed of the vehicle in any known manner, for
example using the speed measuring system of the vehicle itself, or
a speed measuring system independent of the vehicle, e.g., an
acceleration sensor, or by calculations based on the Doppler
effect, etc.
The automatic sensors on vehicle 2 further include a daylight
sensor 14, a rain sensor 16, a vehicle load sensor 18, a
trailer-hitch sensor 20, and a reverse-gear sensor 22.
In addition to the foregoing sensors, the vehicle 2 illustrated in
FIG. 1 includes a brake light 24 at the rear of the vehicle
controlled by a brake light actuator 26. It also includes a
start-up enable device 27 for starting the engine of the
vehicle.
The illustrated vehicle further includes a black box shown at 28.
In this black box are reported every incident in which an alarm
condition was experienced by the vehicle, including pertinent
parameters with respect to the incident, particularly time, speed
of the vehicle, and the distance from the object when the alarm was
triggered. This information may be periodically read out of the
black box and is particularly useful with respect to taxicabs,
trucks, buses, trains, vehicles transporting dangerous cargo (e.g.,
explosives), ambulances, fire department vehicles, etc.
Further, the vehicle includes an automatic actuator 29, e.g. for
actuating the brakes in case of a train, or the steering in case of
an aircraft.
Control Panel
FIG. 2 illustrates one form of control panel 6 for presetting
various parameters into the system, for displaying the status of
the presettable parameters, and for providing the alarms. The
parameters are preset by depressing selected keys in the control
panel, each key being illuminated by a light source when it is
depressed to indicate its depressed condition. Control panel 6
illustrated in FIG. 2 also includes a number of displays, and also
a driving ability testing device which will be described more
particularly below.
With respect to the presettable parameters, control panel 6
illustrated in FIG. 2 includes a group of keys 30 for presetting
the Reaction Time of the driver. Thus, key 30a would be depressed
to indicate a regular reaction time, key 30b would be depressed to
indicate a long reaction time, and key 30c would be depressed to
indicate a very long reaction time. The reaction time would be
influenced primarily by the age of the driver, but could also be
influenced by other factors, e.g., the alertness condition of the
driver, etc.
Control panel 6 includes another group of presettable keys 32 to
indicate the load condition of the vehicle. Thus, depressing key
32a indicates a partial load, key 32b indicates a full load, and
key 32c indicates a trailer is hitched to the vehicle. The
foregoing presettable parameters concerning the load condition of
the vehicle may be used in the absence of the sensors 18 and 20 for
automatically sensing the load of the vehicle and the hitching of a
trailer, respectively, as described earlier with respect to FIG.
1.
Control panel 6 includes two keys 34 indicating the condition of
the road with respect to the danger of skidding thereon by the
vehicle. Thus, key 34a would be depressed to indicate a slippery
condition of the road and therefore a high danger of skidding,
whereas key 34b would be depressed to indicate an unslippery
condition of the road (e.g., dry) and therefore a low danger of
skidding.
Two keys 36 on the control panel 6 indicate the visibility
condition of the road. Thus, key 36a would be depressed where the
visibility condition is high, whereas key 36b would be depressed
where it is low, e.g., because of fog, sandstorm, snow, etc.
Three keys 38 indicate the type of road over which the vehicle is
travelling. Thus, the depression of key 38a indicates an asphalt
road, key 38b a concrete road, and 38c a dirt or gravel road.
Keys 40 indicate the daylight condition while driving. Thus, if it
is daytime key 40a would be depressed, and if it is nighttime key
40b would be depressed.
The control panel 6 includes two keys 42 to select the mode of
operation of the system. Thus, key 42a selects the Collision Danger
mode of operation, wherein the alarm would be actuated whenever a
collision danger is present as will be described below. However, at
times the driver would like to know whether or not his vehicle is
within a predetermined fixed distance behind another vehicle. In
such case, the fixed distance would be selected by keys 44, and key
42b would be depressed to select the Constant Distance mode,
whereupon the system would actuate an alarm whenever the sensed
distance is equal to or less than the selected constant distance.
In the example illustrated in FIG. 2, keys 44 enable the selection
of any one of three distances, namely 50, 100 and 150 meters, by
keys 44a, 44b and 44c, respectively. It will be appreciated,
however, that other parameters and distances, and other means of
selecting such parameters and distances, could be provided in the
control panel 4.
Control panel 6 further includes a front distance display 46, in
which are displayed the distance to the front vehicle (in region
46a), in which direction (by arrow 46b), and whether or not there
is a collision danger (region 46c). A similar display, shown at 48
and having regions 48a, 48b and 48c, is provided with respect to
the rear of the vehicle equipped with the system, whether a rear
collision danger exists, and the status of the rear brake
light.
The actual speed of the vehicle is shown in the speed display 50.
As indicated earlier, this speed may be taken from the conventional
speed measuring system of the vehicle, or may be independently
measured or calculated using the front space sensor, e.g., by the
Doppler effect. Control panel 6 further includes a real time clock
having a time display 52.
Control panel 6 further includes a speaker 54 for producing an
audio alarm in the event of a collision danger, in addition to the
visually-indicated alarms of sections 46c and 48c of the displays
46 and 48. A key 56 on the control panel enables presetting the
volume of the audible alarm.
Control panel 4 further includes a driving ability test device,
generally designated 60, which enables the alertness condition of
the driver to be tested. This device includes a line of depressible
keys 61 and a display 62 controlled by the microcomputer 4 for
randomly displaying sequences in which keys 61 are-to be depressed.
In the example illustrated in FIG. 4, display 62 indicates that
keys 61 are to be depressed in a forward sequence (left to right)
eight times, then depressed in the reverse sequence (right to left)
another eight times, and then to be depressed in the forward
sequence a further eight times. When the driving ability test is to
be conducted, a Start/Stop key 63 is depressed whereupon a timer is
started. When the driver completes the test, he again depresses key
63. The time is measured between the two depressions of key 63
thereby providing an indication of the time required by the driver
to depress the keys according to the required sequences.
This time is a measure of the "alertness" of the driver. It may
thereby be used to provide a parameter of the driver condition and
inputted into the microcomputer 4. In the illustrated system,
however, depressing the displayed sequences of the keys in the
right order within a predetermined time period is a condition
required to be met before the vehicle can be started, as will be
described more particularly below with respect to the flow chart of
FIG. 14. Failure to meet the condition is indicated by display 65,
and passing the condition is indicated by display 64. If one
attempt fails, another attempt may be made by depressing Reset key
66. Such a driving ability test device is particularly useful with
respect to trucks, buses, vehicles carrying dangerous cargoes,
aircraft, and trains, to make sure that the driver is fit to
operate the vehicle before enabling the vehicle for operation.
FIG. 3 illustrates an alternative type of control panel, therein
designated 70, which may be used instead of the control panel 6
illustrated in FIG. 2. Control panel 70 is of the "menu " type, in
which a menu display 71 displays the various categories of
information or options that may be selected or preset into the
computer or displayed in the control panel. The menu display 71 is
controlled by a Select key 72 which advances the display each time
the key is depressed (or continuously until the key is permitted to
return), and an Enter key 73 which enters the selection shown in
the display 71 at the time that key is depressed. In this panel,
the status of the driving conditions is displayed whenever
selections or other displays are not made or shown.
FIG. 4 illustrates the examples of various types of menus which may
be shown in the menu display 71. Thus, one display is the Main Menu
as shown at 75, which lists the various modes of display that may
be selected, namely the following: a Status display, as shown at 71
in FIG. 3; an Alarm Mode Selection display, as shown at 76a (FIG.
4), which enables the selection of the desired Alarm mode, namely
Collision Danger, or Constant Distance; and if Constant Distance is
selected, display 76b enables the selection of the distance; a
Parameters Input mode 77a, which enables selection of the
parameters input, each category of which includes a further display
and enables the selection of one item within the respective
category, as shown by the Reaction Time display 77b; and a Black
Box alarm display 78, which displays the printed data stored within
the black box 28.
By thus utilizing a menu display as shown in FIGS. 3 and 4, it will
be appreciated that a large number of operational modes may be
provided, a large number of parameters may be preset with each
parameter divided into a large number of classifications, and a
large number of displays may be made, in a relatively compact
control panel, as compared to the control panel 6 illustrated in
FIG. 2.
The control panel 70 illustrated in FIG. 3 includes the other
displays and devices shown in FIG. 2, and therefore have been
identified by the same reference numbers to facilitate
understanding.
FIG. 5 illustrates a more complicated driving ability test device
that may be included in the control panel, or in a separate control
panel.
Thus, the driving ability testing device 80 illustrated in FIG. 5
includes, instead of a single line of keys (keys 61 in FIGS. 2 and
3), a matrix of keys 81 arranged in a plurality of horizontal rows
and vertical columns. Device 80 further includes a horizontal
display 82 and a vertical display 83. The horizontal display 82
displays, for each vertical column, the random sequences and
directions in which the keys are to be depressed and the random
number of times such keys are to be sequentially depressed. The
vertical display 83 also displays the random sequence, and a number
of times, the keys in each of the three horizontal rows are to be
depressed. A further display 84 indicates whether the sequencing of
the vertical columns or the horizontal rows is to be effected first
(F) or last (L).
Thus, in the example illustrated in FIG. 5, display 84 indicates
that the random display 82a is to be first executed, and then the
random display 83 is to be executed. Random display 82 indicates
that the first vertical column of keys are to be depressed
consecutively in two sequences starting from the bottom, the middle
column of keys are to be depressed in one sequence, starting from
the top; and the rightmost column of keys are to be depressed
consecutively in three sequences starting from the bottom. Display
83 indicates that the first horizontal line of keys are to be
depressed once from right to left, the second horizontal line of
keys are to be depressed three times, from left to right, and the
third horizontal line of keys are to be depressed twice, from right
to left.
The driving ability testing device 80 illustrated in FIG. 5
includes the other keys of device 60 shown in FIG. 2, namely keys
85, 86, 87 and 88, corresponding to keys 63, 64, 65 and 66,
respectively, in the device of FIG. 2.
The Microcomputer
FIGS. 6a, 6b, are a block diagram illustrating the microcomputer 4
and its inputs and outputs described earlier which enable it to
continuously monitor the operation of the vehicle and to actuate
first a Safety alarm, and then a Collision alarm whenever the
vehicle may enter a danger-of-collision situation according to the
various preset parameters and automatic parameters introduced into
the computer.
The microcomputer 4 as illustrated in FIGS. 6a, 6b is divided into
various functional modules, as follows: a calculation module 90,
which receives data concerning the various parameters briefly
described above and as will be described more particularly below to
enable it to make the necessary computations for actuating the
Safety alarm and the Collision alarm; a real time clock 91 which
keeps track of time in a real time manner; a switches/sensors
output data module 92 which controls the various displays on the
control panel; a deceleration alarm module 93, which controls the
Safety alarm and Collision alarm on the control panel, the brake
light actuator 26 and (e.g., in the case of a train) the vehicle
brakes automatically; a black box module 94, which controls the
information recorded into and read out of the black box 28; and a
driving ability test module 95, involved in the driving ability
test 60 in the control panel of FIG. 2, or 80 in the control panel
of FIG. 5. The operation of each of these modules (except the clock
91) is described more particularly below with reference to the flow
charts of FIGS. 9-14.
Thus, module 90 receives inputs from the front space sensor 8, the
rear space sensor 10, and the vehicle speed sensor 12. Module 90
also receives inputs from the sensors in case there is no
depressible key, e.g., the daylight sensor 14, the trailer sensor
20, the reverse gear sensor 22, the rain sensor 16, and the vehicle
load sensor 18.
With respect to the preset parameters, the module 90 receives as
inputs the reaction time as preselected by keys 30, the vehicle
load condition as preset by keys 32, the skidding danger condition
of the road as preset by keys 34, the visibility condition as
preset by keys 36, the road-type condition as preset by keys 38,
the daylight condition as preset by keys 40, as preset by key
32c.
Computer module 90 also receives an input from the mode selector 42
and the constant distance selector 44, to indicate whether the
system is to operate according to the Collision Danger mode as
preselected by key 42a to actuate the Safety alarm or Collision
alarm whenever the vehicle approaches or is within the computed
danger-of-collision distance, or the Constant Distance mode as
selected by depression of key 42b. In the latter case, the alarm
would be actuated whenever the vehicle is within a fixed distance
as preset by depressing keys 44.
Computer module 90 also receives an input from the driving ability
testing device 60 of FIG. 2 (or 80 of FIG. 5), which introduces the
driver alertness condition as a parameter in the computation to be
made by the computer, and/or as a condition to enable the vehicle
for operation.
Computer module 90 also includes information about the vehicle
braking distances as a function of speed. This is preferably in the
form of a look-up table, for example, provided by the manufacturer
for predetermined defined conditions concerning road type, skidding
danger, vehicle load and tires pressure, and is stored in a ROM
(read-only memory) of the microcomputer so that it can be changed
periodically if necessary.
Computer module 90 also includes information concerning specific
days during the year, or specific hours during the day, which are
defined as dangerous driving days or hours. Examples of the latter
include Saturday nights, Christmas Eve, New Year's Eve, dusk hours,
etc., statistically known as dangerous driving times. This
information could be introduced into the calculations by the
computer in one of the safety factors or coefficients used by the
computer in its calculations.
Computer module 92 controls the various displays, including the
clock display 52, the distance display 46, 48, the speed display 50
and other displays such as the key displays, namely the indicator
lights which illuminate each of the keys (30, etc.) on the control
panel whenever the key is depressed, as described earlier.
The deceleration alarm module 93 controls the Safety and Collision
alarms. As indicated earlier, the Safety alarm is first actuated to
alert the driver that the vehicle is approaching the
danger-of-collision distance from an object, or another rear
vehicle is approaching the danger-of-collision distance. This alarm
may be in the form of an Interrupted Audio alarm from speaker 54
and a Continuous Visual alarm from the collision danger display 46c
or 48c. The Collision alarm, which is actuated when the vehicle is
within the danger-of-collision distance, may be in the form of an
Continuous, Higher-Intensity Audio alarm from speaker 54, and a
Flashing Visual alarm from display region 46c or 48c.
The deceleration alarm module 93 further controls the brake light
actuator 26 to alert drivers that may be trailing the vehicle
involved, and also a brake light actuator display, shown at 26a in
FIG. 6, to indicate this to the driver of the vehicle equipped with
the safety system.
In some vehicles, such as a train or aircraft, the described system
may also be provided with an actuator for automatically effecting a
control of the vehicle, e.g., for automatically actuating the
brakes in a train, or a steering control in an aircraft, in
response to a danger-of-collision condition. This is schematically
indicated by block 96 in FIG. 6 as controlled by the deceleration
alarm module 93.
The black box module 94 controls various displays, generally
indicated by block 97 in FIG. 6b, carried by the black box itself
to read out the information recorded in the black box concerning
alarm incidents which occurred, including the time, speed of the
vehicle, and distance from he object, for each alarm incident.
The driving ability test module 95 controls a start-up enable
device, generally designed 98, which enables the vehicle to be
operated only when the test has been satisfactorily passed, and a
display, such as display 64 in FIG. 2, indicating that the driver
has satisfactorily passed the test and therefore the vehicle is
enabled for operation.
FIG. 7 is a circuit diagram of the microcomputer 4 and the other
components of the electrical system. The microprocessor is
indicated by block 100, its power supply by block 102, and its
watchdog circuit by block 104. It includes a transmitter 106 and a
receiver 108 for transmitting and receiving the pulses (e.g., RF,
ultrasound, laser, IR, etc.) in the front space sensor 8 and the
rear space sensor 10 for measuring the distance of the vehicle from
objects in front of, and to the rear, of the vehicle, respectively.
The microprocessor 100 includes inputs from all the automatic
sensors, and from the presettable keys on the control panel, as
described above. For purposes of example, only one of the sensors,
indicated schematically at 110, and only one of the presettable
keys indicated schematically at 111, are shown as inputs into the
microprocessor. Since the circuit illustrated in FIG. 7 is well
known and commercially available, further details of its structure
and mode of operation are not set forth herein.
Distance Determination
As indicated earlier, the distance of the vehicle from an object is
determined by the front space sensor 8 with respect to objects in
front of the vehicle, and by the rear space sensor 10 with respect
to objects at the rear of the vehicle. Each of these space sensors
may be of known construction, including a transmitter as indicated
at 106 in FIG. 7, and a receiver as indicated at 108. Thus, pulses
are continuously transmitted by each transmitter, and the echoes
from the objects in front of or to the rear of the vehicle are
received by the respective receiver. The computer then measures the
round-trip time from the pulse transmission to the echo reception
in order to determine the distance of the vehicle from the
object.
FIG. 8 illustrates an example of the pattern of pulses transmitted
by the transmitters. Each pulse is identified by a twelve-bit code.
As shown in FIG. 8, the first eight bits do not change and identify
the vehicle transmitting the pulses, whereas the next four bits
change with each transmission and thereby identify the pulse then
being transmitted, such that the computer can compare the return
pulse with the transmitted pulse and thereby determine the
round-trip time of the respective pulse. The receiver is "opened"
to receive echoes for a predetermined "window time" so as to
eliminate echoes from distances which are defined as too long.
OPERATION
General
The operation of the described anti-collision system is illustrated
in the flow charts of FIGS. 9-14. The abbreviations included in the
flow chart are identified by the following table:
TABLE ______________________________________ AS Approach speed A
Maximum permissible time for performing driving ability test AL
Alarm ALSF Alarm stopping front counter ALSR Alarm stopping rear
counter ALCF Alarm collision front counter ALCR Alarm collision
rear counter ALFA Alarm stopping front accumulator ALRA Alarm
stopping rear accumulator AM Alarm mode BD(AS) Braking distance as
a function of approaching speed BF Braking factor CL Carload or
vehicle load CD Collision distance CDM "Constant Distance" mode
distance CSF Collision safety factor DL Daylight/darkness DD
Driving duration DDHF Dangerous driving hours factor FADR Front
alarms to driving duration ratio I Counter ICD Constant Distance
Alarm Counter M Maximum permissible time for checking collision
danger existance in front when at rear there was no danger last
time checked. MD Measured distance RMD Rear MD (measured distance)
RADR Rear alarms to driving duration ratio RV Reverse gear (RV =
`1` when reverse) RT Reaction time RF Reaction factor RP Road type
RRT Rear RT (e.g., RRT=RT+3 Standard deviations) RRF Rear RF (RRF
.gtoreq.1) RBD Rear BD RCL Rear CL RBF Rear BF (RBF .gtoreq.1) RST
Rear ST (RST .gtoreq.1) RSF Rear SF (RSF .gtoreq.1) Rx Receiving
echo RSD Rear stopping distance RCSF Rear CSF SD Stopping distance
SO Sensors output SK Skidding danger ST Stopping factor SF Safety
factor T Time TFA Total front stopping alarms TRA Total rear
stopping alarms TO Time over (for the receiver "window-time") Tx
Transmission command TRx Time of Rx TTx Time of Tx V Vehicle speed
VC Visibility conditions X Trip number
______________________________________
As shown in the foregoing table, many factors are to be included in
making the various computations. These factors may be determined
for each case in order to make the appropriate computation for
actuating the collision alarm, and before it the safety alarm, as
close as possible to the actual conditions at the time of driving,
including the driver conditions, vehicle conditions, and the
environmental conditions as described above. The ALSF and ALSR
counters, the ALCF and ALCR counters, and the ALFA and ALRA
accumulators in the above table, and referred to in the flow charts
below, would be provided in the black box 28 which records all the
incidents in which the safety alarm and collision alarm were
actuated, including the time, vehicle speed and vehicle distance
for each alarm incident.
Overall Operation
The overall operation is illustrated in the flow chart of FIG. 9.
Thus, after the system is reset (block 120), all the parameters are
initialized (block 122), and the pulse transmitters in the front
and rear space sensors 8 and 10 are incremented one pulse count
(block 124), by incrementing the last four bits of the twelve-bit
pulse, as described above with respect to FIG. 8. The pulse is then
transmitted (block 12,5), and the time is measured until its echo
is received within a limited duration (blocks 128, 130). This time
is used for calculating the approach speed of the vehicle with
respect to an object (block 132). The vehicle speed is then
determined, e.g., as read from a speed sensor on the vehicle,, or
as determined independently, e.g., by the Doppler effect (block
134). All the parameters as preset by the presettable keys on the
control panel 6, as well as the outputs from the various sensors as
illustrated in FIG. 1, are then read (block 136), and the computer
then determines whether there is a collision danger, i.e., whether
the measured distance is within the collision-of-danger distance
(block 138). If so, it actuates the alarms; and if not, it returns
to increment and transmit the next pulse (blocks 140 and 142).
Operation of the Calculation Module 90
As indicated earlier, the illustrated system includes two alarms,
namely a Collision alarm which is actuated whenever the measured
distance of the vehicle from an object is within the
danger-of-collision distance as computed by the computer; but
before that alarm is actuated, a Safety alarm is first actuated to
alert the driver that the vehicle is approaching the above
collision alarm distance. For example, the safety alarm may be
actuated when the vehicle is determined to be within a distance
which is increased by 25% as compared to the collision distance, in
which case the collision distance is multiplied by a safety factor
of 1.25 to determine the distance for energizing the safety
alarm.
The foregoing is more clearly illustrated in the flow chart of
FIGS. 10a, 10b which illustrates the operation of the calculation
module 90.
Thus, the system is first initialized as shown by block 150, and
then the various factors concerning the reaction, braking and
stopping distances, and other parameters (representing the rear
vehicle and driver parameters), that are not presettable from the
keyboard, and are read into the computer as indicated by block 152.
The driving date and hour are then read (block 154), and a
determination is made whether that time is a dangerous time (e.g.,
a high-accident rate time, block 156). If so, safety factors (SF
and RSF) are introduced to compensate for this danger time (block
158), before the reaction time (RT), as well as the other
presettable parameters, including approach speed, braking distance
as a function of approach speed, etc., as shown in box 160, are
introduced.
The system then makes the computations illustrated (as an example)
in block 162 to determine the stopping distance SD, which is equal
to the reaction distance plus the braking distance multiplied by a
stopping factor ST and a safety factor SF. In the illustrated
example, the stopping distance is the sum of the reaction distance
and the braking distance. The reaction distance is the product of
the reaction time, visibility condition, daylight condition,
reaction factor and speed; and the braking distance is the product
of the braking distance (as supplied by the manufacturer), road
type, skidding danger, vehicle load and braking factor. The
stopping distance (SD) includes further safety factors, and
determines when the safety alarm will be actuated to first alert
the driver of an approaching collision danger.
A determination is also made of the collision distance CD which is
equal to the stopping distance SD divided by the collision safety
factor CSF, e.g., 1.25 in the example illustrated above, such that
should the distance between the vehicle and the object come within
the collision distance CD, the collision alarm is then
actuated.
The foregoing calculations of stopping distance SD and collision
distance CD with respect to objects at the front of the vehicle are
also made with respect to objects at the rear of the vehicle, these
calculations being RSD and RCD, respectively, also shown in block
162.
Whenever the distance between the vehicle and an object to the
front of the vehicle or to the rear of the vehicle comes within the
stopping distance SD and the collision distance CD, the system
operates according to the deceleration alarm module 93, as
indicated by block 164.
Operation of Deceleration Alarm Module 93
The function of this module is to actuate the safety alarm or
collision alarm, and also the brake light, at the proper time, and
also to record the events within the black box 128. The operation
of this module is more particularly illustrated in FIG.11a-11h.
After the system initializes (block 200), it checks to see whether
the Alarm mode or the Constant Distance mode has been preset (block
202). If the Constant Distance mode has been preset, it
continuously checks to determine whether the measured distance is
less than the preset constant distance, and if so, it actuates the
alarm (blocks 203-207); at the same time, it also increments the
constant distance alarm counter (block 206) in the black box
28.
If the system is in the Collision Danger mode, it continuously
compares the measured distance with the computed stopping distance,
and whenever the measured distance is equal to or less than the
computed stopping distance, it actuates the alarm; at the same
time, it increments an alarm counter (ALSF) and also records the
time, distance and speed in the black box (blocks 208-211).
The above operations are repeated with respect to the rear measured
distance (blocks 212-217). During these operations, the system also
checks to determine whether the vehicle is driving in reverse, and
if so, the reverse stopping distance (RSD) is considered to be the
stopping distance (SD), as shown by blocks 213, 214.
This information is also recorded in the black box (block 217).
During this operation, the system also checks to see whether there
was a problem with the front (block 218); if not, it repeats the
foregoing operations (starting with block 208). If, however, there
was a problem at the front, the system compares the measured
distance with the collision distance (blocks 219, 220). If there is
a collision danger, the Collision alarm is actuated (block 221); at
the same time, the Collision alarm counter in the black box is
incremented (block 222), and the time, distance and speed of the
vehicle are recorded in the black box (block 223). If the system is
included in an anti-collision system for trains, then the actuation
of the collision alarm would also be accompanied by the actuation
of the braking system of the train (block 221).
Where the measured distance was greater than the collision
distance, the system monitors the measured distance now with the
stopping distance and if it is greater than the stopping distance,
the value in counter ALSF is accumulated in accumulator ALFA, and
then the counter is reset to zero (blocks 224-227). The system then
returns to the beginning of the loop, point C.
Whenever the measured distance is equal to or less than the
stopping distance (block 225), the system increments the alarm
stopping front counter (block 228), records the time, distance and
speed in the black box, and also actuates the safety alarm (block
229).
The system also checks to see whether there had been a problem with
the rear the last time this had been checked; if so (i.e., ALSR not
equal to zero), the system proceeds to point E. As will be
described more particularly below, point E checks to determine
whether there is a rear collision danger.
If there had not been a problem with the rear the last time it was
checked, and the last time it was checked is less than a
predetermined maximum time (blocks 231,232), the system again
checks to determine whether there is a collision danger in the
front (point D); but if the maximum time was exceeded, it then
returns to the beginning of the loop (point C).
When it was determined that there is a problem with the stopping
distance which actuated the Safety alarm (block 215) or that there
was a problem with the stopping distance at the rear (block 230),
the system checks whether there is a Collision danger at the rear
(block 233). If the vehicle is being driven in reverse (block 234)
it considers the computed rear collision distance to be the same as
the front collision distance (block 235), and then checks to
determine whether the measured rear distance is equal to or less
than the computed rear collision distance (block 236). If there is
a danger of collision (block 237), the Collision alarm is actuated,
etc. (as described above with respect to point F).
If there is no danger of a rear collision, a check is again made to
determine whether the vehicle is in reverse, and if so, the
computed Rear stopping distance is considered to be the same as the
front stopping distance (blocks 239, 240). The system then checks
to determine whether the rear measured distance is equal to or less
than the computed rear stopping distance (block 241). If the rear
measured distance is greater than the computed rear stopping
distance (block 241), the value in counter ALSR is introduced into
accumulator ALRA, counter ALSR is reset to zero, and the system
then returns to the beginning of the loop, point C.
If, however, the rear measured distance is equal to or less than
the computed stopping distance, the Safety alarm and the brake
light are actuated, and the same operations are repeated with
respect to the information stored in the black box as described
above (blocks 242-244). The system then checks to determine whether
there had not been a previous problem with the front stopping
distance, and whether the last check had been within a previous
time interval. If so, it returns to check the collision danger from
the rear; but if not, it returns to the beginning of the loop at
point C, or continues to check the front collision danger (point D)
if there was a problem at the front (i.e., ALSF is not equal to
"0").
Operation of the Switches/Sensors Module 92
FIGS. 12a, 12b, are a flow chart illustrating the operation of the
switches/sensors output data module 92.
During this operation, the system first reads the presettable
parameters according to the settings of the reaction time key 30
(block 300), the carload-trailer key 32 (block 302), the skidding
danger key 324 (block 304), the visibility condition key 36 (block
306), the road type key 38 (block 308), the daylight key 40 (block
310), the Alarm mode key 42 (block 312), and the constant distance
key 44 (block 314). The system also reads the position of the
reverse gear sensor output schematically shown at 22 in FIG. 1
(block 316), reads or calculates the car speed (block 318), reads
the front and rear car distances (block 320), and reads the clock
time (block 322). The foregoing parameters are displayed by
actuating the clock display 52, the distance displays 46, 48, the
speed display 50, and the key display 30, etc. (block 324). If no
change is made in these settings, the system continues to read or
calculate the car speed, etc., until a change occurs, at which time
the system begins the loop at point A.
Operation of the Black Box Module 94
As indicated earlier, the black box (28, FIG. 1) maintains a record
of all incidents during which the safety alarm and collision alarm
were actuated, recording the time, speed and relative distance
between the vehicle and object for each such occurrence. This
record is accumulated within the black box and may be read out at
any desired time, e.g., by operators of taxicabs, buses, trucks,
trains or aircraft, to provide a record of what occurred during the
vehicle trip. This information can be recorded for a predetermined
number of trips.
The flow chart of FIGS. 13a, 13b more particularly illustrates the
operation of the black box module 94, wherein it will be seen that
a record is made with the driving duration at all times in which
the vehicle is moving during the current trip (block 350), during
which the various accumulators (ALFA and ALRA), and counters (ALSF
and ALSR) are recorded (block 352) and accumulated (block 354).
These are used to calculate the total number of front stopping
alarms and the ratio thereof to the driving duration, and may be
displayed at any time when requested (e.g., by using the blackbox
alarm data menu 78 illustrated in FIG. 4, blocks 356, 358 and 360).
In the same way, the total collision alarms may be calculated and
the ratio thereof to the driving duration.
In the case of trains or aircraft where the vehicle itself was
automatically controlled, e.g., automatic actuation of the brakes
in a train, this is also displayed (block 362 ).
Operation of Driving Ability Test Module 95
FIG. 2 illustrates one form of driving ability test, at 60, and
FIG. 5 illustrates a more complicated driving ability test that may
be used to determine the fitness of the driver to operate the
vehicle. The result of this test may be used as one of the
parameters indicating the condition of a driver to be used in
calculating the collision distance before either the collision
alarm or the safety alarm is actuated. The results of this test may
also be used to disable the operation of the vehicle unless and
until the driver has successfully passed the test. The latter
operation is more particularly illustrated in the flow chart of
FIGS. 14a-14d.
Thus, as shown in FIG. 14a, a counter I, which accumulates the
number of attempts by the driver to pass the test, is first
initialized (block 370), and then a predetermined number A,
representing the maximum permissible time to perform the test, is
read (block 371). With respect to the more complicated device
illustrated in FIG. 5, the random values in the horizontal display
82, vertical display 83, and first/last (F/L) display 84, are then
read into the system (block 373); these set forth the sequences and
directions in which keys 81 are to be depressed and the number of
times in each sequence they are to be depressed.
The driver then depresses the Start/Stop key 85, and then executes
the test depressing the keys 81 according to the random displays
82, 83 and 84, and as soon as this has been completed, the
Start/Stop key 85 is again depressed. These operations are
indicated by blocks 374-381 in FIG. 14. Following this, a
determination is made whether the keys were depressed in the right
order and in the correct number of times as displayed (block 382),
and within the maximum permissible time allowed (blocks 383, 384).
If so, the test was satisfactorily passed, and the operation of the
vehicle is enabled (blocks 385 and 386).
On the other hand, if the test was not satisfactorily passed,
either because the keys were not properly depressed or the
specified time limit was exceeded, the FAIL display 88 is
energized. The system permits the operator to make another attempt
by depressing the reset key 86 provided the maximum number of
attempts had not been exceeded, e.g., ten attempts (blocks
388-393). If the driver failed the test a prescribed number of
times, the vehicle is disabled for a prescribed period (e.g.,
thirty minutes) before the driver can again attempt to pass the
test.
Some Variations
FIGS. 15 and 16 illustrate two further variations that may be made
in the control panel.
FIG. 15 illustrates a control panel which is the same as in FIG. 2,
except for the following changes.
One change is that three further parameters may be preset into the
system, to be taken into consideration in computing the collision
distance and safety distance. Thus, in addition to the other
presettable parameters as illustrated in FIG. 2, the control panel
shown in FIG. 15 includes an additional group of keys 400 for
presetting the tire pressure (which parameter could also be
automatically sensed by a sensor), keys 402 for presetting the road
condition, and keys 404 for presetting whether the vehicle is being
driven in an urban area or on a high speed highway (e.g., a freeway
or toll road).
Another change included in the control panel illustrated in FIG. 15
is that it includes a depressible key 405 marked DTAD, standing for
Dense Traffic Alarm Disable. Thus, this key may be depressed by the
driver when driving in a dense area and, if depressed, would be
effective to disable the alarm whenever the distance to another
object is less than a predetermined minimum distance, or whenever
the speed of the vehicle is less than a predetermined minimum
speed, or whenever the product of the above two factors is less
than a predetermined minimum value.
The control panel illustrated in FIG. 16 is particularly useful for
trains, since it also includes a set of keys 410 indicating many
different load levels, e.g., corresponding to the number of cars in
the train.
In all other respects, the control panels illustrated in FIGS. 15
and 16 may be substantially the same as described above.
While the invention has been described with respect to several
preferred embodiments, it will be appreciated that these are set
forth merely for purposes of example, and that the invention, or
various aspects of the invention, may be advantageously used with
other modifications or in other applications.
* * * * *